Cant cool my 5.9 magnum. Radiator size or add one thing else?

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maca

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Hey all.
I am on my third 5.9 Magnum engine swap into my older 1970 cars.
All of them seem to run fairly hot. I know Australia is a hot climate but they still are too hot. I run a 160 thermostat and then aftermarket aluminium radiator with twin thermo fans. I run a 160 because on the Dyno my car makes 50 horsepower more at 160 that it doesn't 190. But I can't get it to run at 160 as it pretty much always runs around 190 to 210.
I'm now looking at the radiator capacity as these are a truck motor. Can anyone tell me what a Dodge Ram radiator capacity is?
I have cut the middle of the thermostat out and taken it for a drive. It does seem to be a little bit more consistent around 190 now but this was on a cooler night run.
Wishing for anything under 190 with the 5.9 Magnum engine is this unrealistic.
 
They are supposed to run around that temp. If it's not overheating you don't really have a problem. I don't believe 50 hp either. Other things, gauge might not be entirely accurate, Box store water pump with the lesser blades.
 
Whats your setup? (Serprntine Magnum setup,LA style v belt ? water pump,radiator type and shroud you currently have?).....
 
190°F isn't particularly hot, especially if you are driving in a hot climate. 210°F isn't even a problem assuming you are running coolant and a pressurized system.
Besides, I don't think you'll ever get many internal combustion engines to run at much under 180°F, no mater what you do.
 
I can tell you what works for me.
Summer temps here are about 90*F.We rarely have temps over 95*F.I am at 900ft elevation.I have an old 360 block from 1971,with aluminum heads,headers etc,dual 3" all-the-way exhaust,and a 230* @050cam.This, in a 3450 pound 68 Barracuda with a 4-speed,and 3.55s.Car goes 93 in the 1/8th.

I run a 26" factory A/C rad from a 73Dart, matching shroud,and 7psi cap.
I currently run 50% antifreeze, but it cooled slightly better with 100% water
A hi-flow Milodon W/P which is an 8-vane pump with an anti-cavitation plate.
A hi-flow thermostat that maintains a minimum 205*F
Anti-collapse spring in the lower hose.
Restricted bypass hose, and, in summer,blocked heater-hose circuit.
7-qt oilpan with 6 qts or so in it.
Fresh cold air to the carb
14* idle-timing,32* power timing, a 2-stage timing curve, that delivers 28* at 2800rpm, and 32 by 3400.I run a Vcan of 22*, that is all-in very early.
The carb is a little fat on the low-speed circuit.It runs 10.9Scr and 87E10.
A 7-blade A/C clutch-fan with a Thermostatic clutch from a Ford pick-up
I have a slight underdrive on the pulleys, cuz I rev this old girl to 7000 on a regular basis.

The factory temperature gauge never budges from it's "normal" position once the engine is warmed up, No matter the outside temp,nor how long it idles, nor how hard I abuse it.No track-work.Just a rock-solid 205*F.
The truck clutch on the 7-blader is a little noisy when it kicks in, but it reassures me that it is automatically taking care of my engine.And really it ain't near as noisy as the Ford fan was on the pick-up that I first heard this clutch working on;that monster fan roared! The 7 blade Mopar fan is quiet in comparison.
This system has been working since about 2000, no changes. Same hoses, second belt,some ignition timing changes; from time to time I still play with the rate of advance,just a bit.
I gotta tell you tho, same exact system, with a flex-fan and NO fresh-air, was prone to overheat at speeds under 25 mph. I had to maintain a minimum 30mph to keep the factory slow-as-molasses gauge happy, and a 15psi cap to keep the water inside the rad,lol.During this trying time, I removed the factory front license-plate holder, and cut the hole in the hood for fresh air,neither of which helped.The popular-brand flex-fan had to go.
What I learned from this was that at speeds over 30 mph, ram-air thru the rad was sufficient for cooling. But below 25mph, the fan had to be able to pull a lot of air. And the flex-fan no mater what rpm I ran it, just couldn't do it. Whereas even a small diameter 6-blade fixed-wing fan could. I mean that 6 blader was easily 3 or 4 inches smaller than the 7-blader that is on there now.
I won't tell you that you can't make your E-fan work, but are all three of those Magnums cooled that way? If yes, ................
 
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Had a nice big answer typed up and my phone lost it.

Short answer: colder is not better (engine wear increases HUGELY on a cold motor). Run a 15 psi cap and let it heat up to 205-210. That is FAR from overheating. remember, boiling point rises as pressure increases, and water expands as it's heated, so with a sealed cooling system, the actual boiling point is well above 212.
 
As stolen from a quick Google search.

"At one atmosphere, the boiling point for water is 212°F or 100°C. A 10 psi pressure cooker will bring the boiling point to 240°F, but a 15 psi pressure cooker will top at250°F. In other words, the boiling point increases at a decreasing rate against increasing pressure."
 
It is about 3 degrees for every lb of pressure.....so if you have a 7 lb. cap you can add 21 degrees to 212 to get your boiling point...So about 233 degrees....
 
bbrroowwnn said:
It is about 3 degrees for every lb of pressure.....so if you have a 7 lb. cap you can add 21 degrees to 212 to get your boiling point...So about 233 degrees....
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I had a very hot 406 sbc, that ran a little hot. a mech. friend told me to take the 160 thermostat out and try a 180, guess what, it worked on the chevy. why ? I don`t know, other than keeping the coolant in the rad. longer.????
 
famous bob said:
I had a very hot 406 sbc, that ran a little hot. a mech. friend told me to take the 160 thermostat out and try a 180, guess what, it worked on the chevy. why ? I don`t know, other than keeping the coolant in the rad. longer.????
Click to expand...
bingo.....you need to keep the coolant in the radiator long enough to cool it....If it doesn't stay in the radiator long enough, it doesn't matter what size radiator you have , how many cores, aluminum, etc.....
 
Maca, all seems normal for the temps you listed.
 
Abodybomber said:
-What's your setup? (Serprntine Magnum setup,LA style v belt ? water pump,radiator type and shroud you currently have?).....
Click to expand...
- All of that is important, plus the crank pulley should be larger, in diameter, than the water pump/fan pulley.
 
I'm about to drop a 500 HP magnum into an A Body... Going to run a viscous fan and 2 core alum radiator with shroud in South Texas. I'm nervous now.
 
I wouldn't be. Sizeable radiator correct? OE size or greater?
 
My 367 is only a bit over 400hp, but I would not be afraid to tow a trailer to Texas.
Most dyno engine oils begin to smoke at 240ish. I'm guessing a little under that would then be the upper limit of hot.Unless of course you have mechanical issues like; the the valve stems start sticking,or pistons getting stuck,etc.But that's why I run a 7qt pan; it puts the cooling oil where it needs to be. Also why I run dual 3"exhaust, so the heat can get away. Also why the lowspeed circuit is a little fat; it sucks some heat out of the chamber.
The rad isn't the only way to get rid of heat.
 
Hey guys
Thanks for the reply's. I am running the factory pulley and Serpentine Magnum setup. The main reason for wanting the engine to run cooler is the under bonnet temp feels very hot. After a cruise I can not touch things like the brake booster etc as the whole engine bay is stinking hot. The heat coming from under the car at idle feels like an oven on high with a fan. It comes through the firewall and makes the car very hot to cruise during the day.
The other reason is the HP. The 50hp loss was with a holley blow through carb. I tried to get it sorted but it hated the heat. I think it may have been boiling fuel. On the dyno it would consistently run 380hp at 190F or above. But let it cool to 160 and I easily get 430 HP at the wheels every time.
I have now switched to a Fitech throttle body injection as I spend a heap of money on the dyno but it still ran like crap. The fitech seems to handle the heat much better but it has not been on the dyno with the Fitech yet.
The other day I pulled the centre out of the thermostat and with only limited testing it looks better. I am hovering around 190 to 195 but will have to have a few more runs.
I am running twin thermos fans with shrouds. They use these fans here in Australia to cool our performance factory V8 turbo cars so I think they should do the job foe me. I am running a bigger ally radiator with a tight fin count but the radiator is a $200 ebay one that I fit after the factory radiator couldn't keep the engine cool. I run 32 degrees timing at cruise. I have tried 40 but it doesn't seem to make any difference at all.
I will run it over the next few days and if it wants to run at 195 then I will have to just be happy there. It seemed to cruise down the highway at 160 for an hour then all of a sudden it would hit 200 for no reason but with the middle of the thermostat taken out it seems to be more consistent now.
The under bonnet temp seems excessive. Maybe I need a scoop or to coat or wrap my headers. Also my intake air temp at cruise is 100F and that's after its gone through the intercooler.

AJ/FormS These thermos fans apparently pull 3000cfm but I do have a fan from a dodge ram here. I was going to try it but wasn't sure if it would be any good in traffic. We don't have much dodge stuff in Australia so we don't know much about them. Is this fan any good? It has 52027999 stamped into the blade. I will post a pic now.
20170220_2146391.jpg
 
hook up the vacuum advance and get around 48-50* at highway cruise. Running vacuum advance improves fuel economy at cruise and lowers cylinder temp. At cruise you have a leaner mixture on a proper tune and need to light the fire earlier. IMO mechanical advance only is for race cars, idle to WOT to idle.
 
That clutch with the little spring on it is the right one to run.
But
Are you saying that your engine is turbo charged?
It would have been nice if you had mentioned that in post #1.

If you put a turkey in the oven,it cooks. If you turn the oven off, and put the oven and the turkey still in it, into a furnace, it will still cook, even tho the oven is off,right?
I'm assuming now that the turbo is under the hood,right? and that the intercooler is up front in the airstream right? And that after the HOT Australian air has passed through the intercooler, now its's really,really HOT, and that really,really HOT air next passes through the rad.It may in fact be so hot, it cannot cool the engine coolant at all, so your engine is cooking in the furnace, called Underhood.
Please tell me I'm wrong and that the intercooler exhaust air is not getting in front of the rad!
..
 
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Yes one of my cars is supercharge with a vortech blower but not turbo. If i disconnect the supercharger it still runs hot. I will take it for a few more test runs over the next few days and hopefully the steadier temps continue with middle out of the thermostat.
If i want to run that fan i will need to change my water pump as for some reason my water pump doesn't have the thread on the front to screw the fan onto.
 
maca said:
Hey all.
I run a 160 because on the Dyno my car makes 50 horsepower more at 160 that it doesn't 190.
Click to expand...



Your expectations are... High. Put a stock thermostat in there and leave it be.
 
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AJ/FormS said:
Ok so same question; Where is intercooler air exhausting?
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The intercooler is in front of the radiator and takes up around half of it. I did run this engine with no intercooler for a few months and it had the same issues. I couldn't get out in it today because after it ran fine on e85 over the weekend, but today it decided to rev high and then keep stalling. But will try over the next few days and if it is consistent and doesn't jump around I will just have to be happy with 190 to 200. But I would stilly bonnet and not singe my hair from the heat.lol So I might ad a scoop to help the engine bay temps
I will try to get Fitech to sort out why its doing this all of a sudden. Idles fine for 30 seconds and then loses idle control. I might have to switch back to petrol until I get the heat sorted.
 
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